Transformations of β-aryl-N-Cbz-α,β-didehydro-α-amino esters with hydrazine hydrate

Cyclizations of Cbz-protected -didehydro- -arylalanine esters with excess hydrazine hydrate afforded mixtures of the expected 3-pyrazolidinones and the unexpected 1-amino-5-benzylidenehydantoins and -Cbz- -arylalanine hydrazides . Presumably, the pyrazolidinones and hydantoins are formed as primary...

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Published inZeitschrift für Naturforschung. B, A journal of chemical sciences Vol. 71; no. 6; pp. 623 - 631
Main Authors Drev, Miha, Grošelj, Uroš, Svete, Jurij
Format Journal Article
LanguageEnglish
Published BERLIN De Gruyter 01.06.2016
Walter De Gruyter
Subjects
amino acids
Chemistry
Chemistry, Inorganic & Nuclear
Chemistry, Organic
cyclization
hydantoins
Physical Sciences
pyrazolidinones
reduction
Science & Technology
PEPTIDES
pyrazolidinones
AMINO-ACIDS
amino acids
reduction
cyclization
hydantoins
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Summary:Cyclizations of Cbz-protected -didehydro- -arylalanine esters with excess hydrazine hydrate afforded mixtures of the expected 3-pyrazolidinones and the unexpected 1-amino-5-benzylidenehydantoins and -Cbz- -arylalanine hydrazides . Presumably, the pyrazolidinones and hydantoins are formed as primary products competitive 1,2- and 1,4-addition of hydrazine hydrate followed by cyclization, whereas -arylalanine hydrazides are formed as secondary products reductive cleavage of the C(5)–N(1) bond in pyrazolidinones . The overall selectivity depends on the reaction time and on the -substituent in the starting dehydroalanine ester
ISSN:0932-0776
1865-7117
DOI:10.1515/znb-2015-0221